| 1 | /** @file
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| 2 | * IPRT - Handle Tables.
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| 3 | */
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| 4 |
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| 5 | /*
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| 6 | * Copyright (C) 2011 Oracle Corporation
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| 7 | *
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| 8 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 9 | * available from http://www.virtualbox.org. This file is free software;
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| 10 | * you can redistribute it and/or modify it under the terms of the GNU
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| 11 | * General Public License (GPL) as published by the Free Software
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| 12 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 13 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 14 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 15 | *
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| 16 | * The contents of this file may alternatively be used under the terms
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| 17 | * of the Common Development and Distribution License Version 1.0
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| 18 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 19 | * VirtualBox OSE distribution, in which case the provisions of the
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| 20 | * CDDL are applicable instead of those of the GPL.
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| 21 | *
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| 22 | * You may elect to license modified versions of this file under the
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| 23 | * terms and conditions of either the GPL or the CDDL or both.
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| 24 | */
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| 25 |
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| 26 | #ifndef ___iprt_handletable_h
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| 27 | #define ___iprt_handletable_h
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| 28 |
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| 29 | #include <iprt/cdefs.h>
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| 30 | #include <iprt/types.h>
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| 31 |
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| 32 | RT_C_DECLS_BEGIN
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| 33 |
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| 34 | /** @defgroup grp_rt_handletable RTHandleTable - Handle Tables
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| 35 | * @ingroup grp_rt
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| 36 | * @{
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| 37 | */
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| 38 |
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| 39 | /**
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| 40 | * Callback for retaining an object during the lookup and free calls.
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| 41 | *
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| 42 | * This callback is executed when a handle is being looked up in one
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| 43 | * way or another from behind the handle table lock. This allows you
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| 44 | * to increase the reference (or some equivalent thing) during the
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| 45 | * handle lookup and thereby eliminate any race with anyone trying
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| 46 | * to free the handle.
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| 47 | *
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| 48 | * Note that there is no counterpart to this callback, so if you make
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| 49 | * use of this you'll have to release the object manually of course.
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| 50 | *
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| 51 | * Another use of this callback is to do some extra access checking.
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| 52 | * Use the return code to indicate whether the lookup should fail
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| 53 | * or not (no object is returned on faliure, naturally).
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| 54 | *
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| 55 | * @returns IPRT status code for the lookup (the caller won't see this).
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| 56 | *
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| 57 | * @param hHandleTable The handle table handle.
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| 58 | * @param pvObj The object which has been looked up.
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| 59 | * @param pvCtx The context argument if the handle table was created with the
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| 60 | * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL.
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| 61 | * @param pvUser The user context argument specified when creating the table.
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| 62 | */
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| 63 | typedef DECLCALLBACK(int) FNRTHANDLETABLERETAIN(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, void *pvUser);
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| 64 | /** Pointer to a FNHANDLETABLERETAIN. */
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| 65 | typedef FNRTHANDLETABLERETAIN *PFNRTHANDLETABLERETAIN;
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| 66 |
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| 67 | /**
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| 68 | * Callback for deleting a left over object during RTHandleTableDestroy.
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| 69 | *
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| 70 | * @param hHandleTable The handle table handle.
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| 71 | * @param h The handle.
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| 72 | * @param pvObj The object.
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| 73 | * @param pvCtx The context argument if the handle table was created with the
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| 74 | * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL.
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| 75 | * @param pvUser The user context argument specified when creating the table.
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| 76 | *
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| 77 | */
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| 78 | typedef DECLCALLBACK(void) FNRTHANDLETABLEDELETE(RTHANDLETABLE hHandleTable, uint32_t h, void *pvObj, void *pvCtx, void *pvUser);
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| 79 | /** Pointer to a FNRTHANDLETABLEDELETE. */
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| 80 | typedef FNRTHANDLETABLEDELETE *PFNRTHANDLETABLEDELETE;
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| 81 |
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| 82 |
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| 83 | /** @name RTHandleTableCreateEx flags
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| 84 | * @{ */
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| 85 | /** Whether the handle table entries takes a context or not.
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| 86 | *
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| 87 | * This can be useful for associating a handle with for instance a process or
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| 88 | * similar in order to prevent anyone but the owner from using the handle.
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| 89 | *
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| 90 | * Setting this means you will have to use the WithCtx functions to do the
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| 91 | * handle management. */
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| 92 | #define RTHANDLETABLE_FLAGS_CONTEXT RT_BIT_32(0)
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| 93 | /** Whether the handle table should take care of the serialization.
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| 94 | * If not specified the caller will have to take care of that. */
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| 95 | #define RTHANDLETABLE_FLAGS_LOCKED RT_BIT_32(1)
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| 96 | /** The mask of valid flags. */
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| 97 | #define RTHANDLETABLE_FLAGS_MASK UINT32_C(0x00000003)
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| 98 | /** @} */
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| 99 |
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| 100 |
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| 101 | /**
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| 102 | * Creates a handle table.
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| 103 | *
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| 104 | * The handle table translates a 32-bit handle into an object pointer,
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| 105 | * optionally calling you back so you can retain the object without
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| 106 | * racing RTHandleTableFree.
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| 107 | *
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| 108 | * @returns IPRT status code and on success a handle table handle will be stored at the
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| 109 | * location phHandleTable points at.
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| 110 | *
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| 111 | * @param phHandleTable Where to store the handle table handle on success.
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| 112 | * @param fFlags Flags, see RTHANDLETABLE_FLAGS_*.
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| 113 | * @param uBase The handle base value. This is the value of the
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| 114 | * first handle to be returned.
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| 115 | * @param cMax The max number of handles. When exceeded the RTHandleTableAlloc
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| 116 | * or RTHandleTableAllocWithCtx calls will fail. Note that this
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| 117 | * number will be rounded up to a multiple of the sub-table size,
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| 118 | * or if it's too close to UINT32_MAX it will be rounded down.
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| 119 | * @param pfnRetain Optional retain callback that will be called from behind the
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| 120 | * lock (if any) during lookup.
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| 121 | * @param pvUser The user argument to the retain callback.
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| 122 | */
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| 123 | RTDECL(int) RTHandleTableCreateEx(PRTHANDLETABLE phHandleTable, uint32_t fFlags, uint32_t uBase, uint32_t cMax,
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| 124 | PFNRTHANDLETABLERETAIN pfnRetain, void *pvUser);
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| 125 |
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| 126 | /**
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| 127 | * A simplified version of the RTHandleTableCreateEx API.
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| 128 | *
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| 129 | * It assumes a max of about 64K handles with 1 being the base. The table
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| 130 | * access will serialized (RTHANDLETABLE_FLAGS_LOCKED).
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| 131 | *
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| 132 | * @returns IPRT status code and *phHandleTable.
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| 133 | *
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| 134 | * @param phHandleTable Where to store the handle table handle on success.
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| 135 | */
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| 136 | RTDECL(int) RTHandleTableCreate(PRTHANDLETABLE phHandleTable);
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| 137 |
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| 138 | /**
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| 139 | * Destroys a handle table.
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| 140 | *
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| 141 | * If any entries are still in used the pfnDelete callback will be invoked
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| 142 | * on each of them (if specfied) to allow to you clean things up.
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| 143 | *
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| 144 | * @returns IPRT status code
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| 145 | *
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| 146 | * @param hHandleTable The handle to the handle table.
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| 147 | * @param pfnDelete Function to be called back on each handle still in use. Optional.
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| 148 | * @param pvUser The user argument to pfnDelete.
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| 149 | */
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| 150 | RTDECL(int) RTHandleTableDestroy(RTHANDLETABLE hHandleTable, PFNRTHANDLETABLEDELETE pfnDelete, void *pvUser);
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| 151 |
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| 152 | /**
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| 153 | * Allocates a handle from the handle table.
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| 154 | *
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| 155 | * @returns IPRT status code, almost any.
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| 156 | * @retval VINF_SUCCESS on success.
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| 157 | * @retval VERR_NO_MEMORY if we failed to extend the handle table.
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| 158 | * @retval VERR_NO_MORE_HANDLES if we're out of handles.
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| 159 | *
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| 160 | * @param hHandleTable The handle to the handle table.
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| 161 | * @param pvObj The object to associate with the new handle.
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| 162 | * This must be aligned on a 4 byte boundary.
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| 163 | * @param ph Where to return the handle on success.
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| 164 | *
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| 165 | * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
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| 166 | */
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| 167 | RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void *pvObj, uint32_t *ph);
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| 168 |
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| 169 | /**
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| 170 | * Looks up a handle.
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| 171 | *
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| 172 | * @returns The object pointer on success. NULL on failure.
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| 173 | *
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| 174 | * @param hHandleTable The handle to the handle table.
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| 175 | * @param h The handle to lookup.
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| 176 | *
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| 177 | * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
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| 178 | */
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| 179 | RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h);
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| 180 |
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| 181 | /**
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| 182 | * Looks up and frees a handle.
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| 183 | *
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| 184 | * @returns The object pointer on success. NULL on failure.
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| 185 | *
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| 186 | * @param hHandleTable The handle to the handle table.
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| 187 | * @param h The handle to lookup.
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| 188 | *
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| 189 | * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
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| 190 | */
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| 191 | RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h);
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| 192 |
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| 193 | /**
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| 194 | * Allocates a handle from the handle table.
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| 195 | *
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| 196 | * @returns IPRT status code, almost any.
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| 197 | * @retval VINF_SUCCESS on success.
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| 198 | * @retval VERR_NO_MEMORY if we failed to extend the handle table.
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| 199 | * @retval VERR_NO_MORE_HANDLES if we're out of handles.
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| 200 | *
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| 201 | * @param hHandleTable The handle to the handle table.
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| 202 | * @param pvObj The object to associate with the new handle.
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| 203 | * This must be aligned on a 4 byte boundary.
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| 204 | * @param pvCtx The context to associate with the new handle.
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| 205 | * @param ph Where to return the handle on success.
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| 206 | *
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| 207 | * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
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| 208 | */
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| 209 | RTDECL(int) RTHandleTableAllocWithCtx(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, uint32_t *ph);
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| 210 |
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| 211 | /**
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| 212 | * Looks up a handle.
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| 213 | *
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| 214 | * @returns The object pointer on success. NULL on failure.
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| 215 | *
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| 216 | * @param hHandleTable The handle to the handle table.
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| 217 | * @param h The handle to lookup.
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| 218 | * @param pvCtx The handle context, this must match what was given on allocation.
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| 219 | *
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| 220 | * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
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| 221 | */
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| 222 | RTDECL(void *) RTHandleTableLookupWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx);
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| 223 |
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| 224 | /**
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| 225 | * Looks up and frees a handle.
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| 226 | *
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| 227 | * @returns The object pointer on success. NULL on failure.
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| 228 | *
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| 229 | * @param hHandleTable The handle to the handle table.
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| 230 | * @param h The handle to lookup.
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| 231 | * @param pvCtx The handle context, this must match what was given on allocation.
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| 232 | *
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| 233 | * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation.
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| 234 | */
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| 235 | RTDECL(void *) RTHandleTableFreeWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx);
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| 236 |
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| 237 | /** @} */
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| 238 |
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| 239 | RT_C_DECLS_END
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| 240 |
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| 241 |
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| 242 | #endif
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| 243 |
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